In normal straight line stitching operations employed in sewing machines, the eye of the needle is maintained in vertical alignment with the point of the hook at all times. When zig-zag stitching operations are utilized, this vertical alignment is not maintained, and the needle eye moves upward or downward out of vertical alignment during the pivoting action of the needle bar necessitated for zig-zag operation. While some degree of misalignment can be tolerated, The bight or stitch width obtainable in zig zag sewing machines for home use is limited to a narrow range, typically about six millimenters, because the inconsistencies in the loop forming operation produced because of misalignment become excessive beyond this range.
The present invention overcomes the misalignment problem by causing the needle eye to track with the point of the hook in continous proper vertical alignment during the entire stitching operation, thus eliminating the inconsistencies in the loop forming operation and the resultant narrow bight or stitch width range limitation.